package demo2;

public class UserNameException extends RuntimeException{//若继承的是Exceptiion，（受查异常）则loginInfo()必须要声明throws UserNameException,PasswordException
     //自定义异常一定要继承于某个异常

    public UserNameException() {
    }

    public UserNameException(String message) {
        super(message);
    }
}
